A megaphone, with a three-inch lighter to scale.

An electronic megaphone.

A megaphone, speaking-trumpet, bullhorn or loud hailer is a portable, usually hand-held, funnel-shaped device whose application is to send a person’s natural voice toward a targeted direction for a specified purpose. This is accomplished by channeling the sound through a funnel, which also serves to match the impedance of the voice cords to the air. The natural human voice tends to spread evenly in all directions, whereas when it is sent through a megaphone, the sound is concentrated in a given direction and the coupling of its energy to the air optimised. [1]. The trade-off is that if a listener is to the side, it is more difficult to hear what is being said. An electronic megaphone amplifies sound to a higher decibel level. It consists of a microphone, an amplifier and a loudspeaker. Image File history File linksMetadata Download high-resolution version (2749x2109, 531 KB) This image was copied from wikipedia:en. ... Image File history File linksMetadata Download high-resolution version (2749x2109, 531 KB) This image was copied from wikipedia:en. ... Image File history File links Download high-resolution version (600x800, 91 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Megaphone ... Image File history File links Download high-resolution version (600x800, 91 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Megaphone ... In electrical engineering, Impedance is a measure of opposition to a sinusoidal electric current. ... The human voice consists of sound made by a human using the vocal folds for talking, singing, laughing, screaming. ... The decibel (dB) is a logarithmic unit of measurement that expresses the magnitude of a physical quantity (usually power) relative to a specified or implied reference level. ... A Neumann U87 capacitor microphone A microphone, sometimes referred to as a mike or mic (both IPA pronunciation: ), is an acoustic to electric transducer or sensor that converts sound into an electrical signal. ... Generally, an amplifier is any device that uses a small amount of energy to control a larger amount of energy. ... “Loudspeaker” redirects here. ...

Inventor Thomas Edison exhibited an early version of the megaphone at the Paris Exposition.^{[citation needed]} Thomas Alva Edison (February 11, 1847 – October 18, 1931) was an American inventor and businessman who developed many devices which greatly influenced life around the world. ... The third Paris Worlds Fair, called an Exposition Universelle in French was held in 1878 and celebrated the recovery of France after the crushing defeat of the 1870 Franco-Prussian War. ...

Common uses for megaphones are at sporting events, political functions and generally when one needs to address congregations of people in open spaces. Police officers often use them to communicate with suspects and rescue crews during operations to communicate with the victim. Politics is the process by which decisions are made within groups. ...

An electronic Bullhorn is the trademark of Legendary Wrestling Manager, Jimmy Hart. The Mouth of the South Jimmy Hart (also known as The Colonel) (born January 1, 1943 in Memphis, Tennessee) is a professional wrestling manager, executive, composer and musician. ...

See Also

• Horn (acoustic)
• Horn speaker

A horn is a tapered sound-guide designed to provide an acoustic impedance match between a sound-producing device and the characteristic impedance of free space. ... Horn loudspeaker schematic. ...

References

1. See Example 1 of Impedance Matching for description of amplification mechanism